1. Field of the Invention
The present invention relates to a combination master link and chain shortener device for use in chain link sling assembly applications that can be readily attached to existing closed loop lifting rings.
2. Prior Art
Various types of chain slings are widely known and utilized to secure and to lift loads. In many instances, a main or master link portion connects to a lifting device such as, but not limited to, a hook and in turn lifting equipment such as a crane or block. The main or master link also retains a chain or chains which are, in turn, secured to a load to be lifted. The present device, thus, resides and operates between a lifting device and a load.
Various examples of chain slings utilizing various types of master links are known in the prior art. Likewise, various types of chain shorteners have been devised to adjust the length of the chain or the chains as necessary.
For example, Archer (U.S. Pat. No. 4,176,874) discloses a combination lifting ring with chain shortener features incorporated.
Fredriksson (U.S. Pat. No. 5,775,754) discloses a unitary chain coupler with a pair of projections having vertical seating surfaces for shortening loops at a far end of the coupler and a pair of intermediate chain anchoring projections.
Millington (U.S. Pat. No. 4,556,246) discloses a chain link assembly having two half link portions connected by a pin.
It is, therefore, desirable to provide a combination master link and chain shortener so that the length of the chains are easily adjustable in the field.
It is further desirable to provide a combination master link and chain shortener wherein multiple lengths of chain may be attached to the device quickly and simply in the field.
It is also desirable to provide a combination master link and chain shortener that can be readily separated for connecting to other closed loop lifting rings.
It is also desirable to provide a combination master link and chain shortener having a single chain retaining pin for retaining all chains.
It is also desirable to provide a combination master link and chain shortener reducing the number of fittings normally required with existing designs for chain sling assemblies of more than two legs.
The above references and prior art require an intermediate fitting in order to attach a combination master link and chain shortener to a closed loop main or master link for the express purpose of creating a chain sling assembly of more than two legs. Therefore, it is desirable to provide a combination master link and chain shortener that can be attached directly, without the need for additional special fittings, to a closed loop main or master link.